It is common practice to load cartridges into a firearm magazine by progressive compression of the magazine's spring. The cartridges are inserted one at a time against the ever increasing spring resistance as the magazine approaches a fully-loaded condition. If the next cartridge is simply loaded against the previously loaded cartridge, it is recognized that considerable force and manual dexterity are required.
The unaided loading of a firearm magazine is time consuming and difficult, especially when trying to push in the last few cartridges into the magazine. Moreover, loading by pressing down with one's fingers without any manual assistance can lead to misalignment of cartridges within the magazine and possible jamming of the cartridges. In order to overcome such problems, there have been many different types of manual devices that have been developed to aid in magazine loading.